
			Startup configuration

*INTRO
Yacas allows you to configure a few things at startup. The file
{~/.yacasrc} is written in the Yacas language and
will be executed when Yacas is run. The
following functions can be useful in the {~/.yacasrc} file.

*CMD DefaultDirectory --- add directory to path for Yacas scripts
*CORE
*CALL
	DefaultDirectory(path)

*PARMS

{path} -- a string containing a full path where yacas script files reside

*DESC

When loading files, yacas is also allowed to
look in the folder "path". {path} will be prepended
to the file name before trying to load the file.
This means that "path" should end with a forward slash (under Unix-like
operating systems).

Yacas first tries to load a file from the current
directory, and otherwise it tries to load from
directories defined with this function, in the
order they are defined. Note there will be at least one directory
specified at start-up time, defined during compilation. This
is the directory Yacas searches for the initialization scripts
and standard scripts.

*E.G.

	In> DefaultDirectory("/home/user/myscripts/");
	Out> True;

*SEE Load, Use, DefLoad, FindFile

*CMD PrettyPrinter --- set routine to use as pretty-printer

*STD

*CALL
	PrettyPrinter(printer)

*PARMS

printer - a string containing the name of a function that can
pretty-print an expression

*DESC

This function sets up the function printer to print out the results on
the command line. This can be reset to the internal printer with {PrettyPrinter()}.

*E.G.

	In> Taylor(x,0,5)Sin(x)
	Out> x-x^3/6+x^5/120;
	In> PrettyPrinter("PrettyForm");
	
	True
	
	Out>
	In> Taylor(x,0,5)Sin(x)
	
	     3    5
	    x    x
	x - -- + ---
	    6    120
	
	Out>
	In> PrettyPrinter();
	Out> True;
	In> Taylor(x,0,5)Sin(x)
	Out> x-x^3/6+x^5/120;

*SEE PrettyForm, Write

*CMD Help --- get documentation for some command
*STD
*CALL
	Help()
	Help(function)

*PARMS

function - a string containing the name of a function to show help for

*DESC

When help is requested by the user, by typing {?}function or {??}, the functions {Help()} (for {??}) and {Help(}function{)} (for {?}function) are called.  By default, {lynx} is used as a
browser (another recommended text-only browser is {links}). The help resides in the subdirectory {documentation/} under the directory the math scripts
were installed in. So the help files can be found using {FindFile}.

The function {Help} is auxiliary and should not be used to actually get online help.

*E.G.

To use netscape for browsing help, enter the following commands:

	Help(_f) <-- SystemCall("netscape " :
	  FindFile("documentation/ref.html"):"#":f);
	Help() := SystemCall("netscape " :
	  FindFile("documentation/books.html"));

*SEE SystemCall, FindFile

*CMD HistorySize --- set size of history file
*CORE
*CALL
	HistorySize(n)

*PARMS

{n} -- number of lines to store in history file

*DESC

When exiting, yacas saves the command line history to a
file {~/.yacas_history}. By default it will only
save the last 50 lines, to save space on the hard disk. This can be
overridden with this function. Passing -1 tells the system to save <i>all</i>
lines.

*E.G.

	In> HistorySize(200)
	Out> True;
	In> quit

